A typical liquid crystal display (LCD) includes a passive optical liquid crystal panel and a backlight module to provide sufficient illumination for the liquid crystal panel, so that the LCD can display images.
FIG. 7 is an exploded, isometric view of a typical LCD. The typical LCD 100 includes a liquid crystal panel 19 and a backlight module 10. The backlight module 10 includes a light shield member 110, a plurality of light emitting diodes (LEDs) 120, an optical film set 130, a light guiding plate (LGP) 140, a frame 150, a reflector 160, and a bezel 180.
The LGP 140 includes a bottom surface 142 and a light incident surface 143 adjoining the bottom surface 142. The frame 150 includes four sidewalls 151 that cooperatively define an accommodating space (not labeled), and a plurality of grooves (not labeled) formed at one of the sidewalls 151. A rectangular adhesive tape 162 is affixed along the edges of the reflector 160.
In assembly, the LGP 140, the optical film set 130, and the light shield member 110 are received in the accommodating space. Each LED 120 is received in a corresponding groove and adjacent to the light incident surface 143. The reflector 160 is received in the bezel 180. The frame 150, the LGP 140, the optical film set 130, the light shield member 110, and the plurality of LEDs 120, are positioned onto the reflector 160. The bottom surface 142 is attached to the reflector 160 via the adhesive tape 162. The liquid crystal panel 19 is positioned onto the backlight module 10 forming the LCD 100.
In operation, incident light beams are emitted from the LEDs 120 to the LGP 140. A part of the light beams are emitted out from the bottom surface 142 and reflected back into the LGP 140 by the reflector 160. The LGP 140 guides both the incident and reflected light beams to the liquid crystal panel 19.
A typical thickness of the adhesive tape 162 is usually in a range from about 0.03 to about 0.05 millimeters, to ensure adhesion between the LGP 140 and the reflector 160. However, the typical thickness may induce a gap between the LGP 140 and the reflector 160. Light beams emanating from the bottom surface 142 of the LGP 140 may be consumed in the gap. As a result, the light utilization efficiency of the backlight module 10 is low and the brightness of the LCD 100 is degraded.
Therefore, a backlight module and an LCD employing such backlight module is desired to overcome the above-described deficiencies.